The jessour of southern Tunisia: Sustainable agriculture in arid areas and protection against erosion

The jessour is an ancient technique for collecting runoff water in the arid lands of southern Tunisia, particularly in the municipalities of Beni Khiar, Medéine, Gabs, Matmata and Tataouine. These structures, situated at altitudes of between 400 and 600 metres with annual rainfall of 100 to 150 mm, consist of a hydraulic system comprising the jisr (retaining wall), the terrace (cultivation area with fruit trees and other trees) and the impulvo (runoff catchment area). The impulvo captures and channels runoff water, bounded by a natural dividing line, and can receive surplus water from upstream units. Each unit receives between 300 and 500 mm of additional runoff annually. With some 35,000 jisr in the region, the jessour ensure local self-sufficiency, supply neighbouring areas with products such as olive oil, dried figs and dates, and reduce soil erosion, acting as natural barriers that promote sustainable water management in arid environments.